Home > Publications database > Optische Datenspeicherung mit Phasenwechselmedien: Präparation und Charakterisierung von GeSbTe-Schichten |
Book/Report | FZJ-2020-00427 |
2000
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/23980
Report No.: Juel-3775
Abstract: Data storage plays a major role in information technology. The further development of thecompact disc for mass storage does not only require an increase of the data density butalso the ability to delete or to rewrite data. Phase change materials have a high potentialfor rewriteable optical date storage. The aim of this thesis is to investigate and comparethe material's properties of Ge$_{2}$Sb$_{1}$Te$_{5}$ (PC1) and Ge$_{4}$Sb$_{1}$Te$_{5}$ (PC2) with regard to therequirements of data storage application. The large change of the electrical resistance is used to investigate the phase changekinetics. Accompanying x-ray diffraction measurements show that PC1 undergoes a phasetransitions from an amorphous to a cubic phase and a second to a hexagonal phase. On thecontrary, PC2 shows only one transition from amorphous to fcc. The cubic phase of bothalloys agrees qualitatively to a NaCl- structure but for PC1 a high density of vacanciesis postulated. The optical contrast between the two crystalline phases of PC1 is small(4.5%) compared to that between the amorphous and the fcc-phase (66%). Nevertheless,selected area (electron) diffraction showed clearly the fcc-character of laser modified areas.Measurements on PC-films with a thin ZnS-SiO$_{2}$ layer on top show that the impact ofthe dielectric layer an the phase change properties of both alloys is not neglectable.
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